Legacy of Acid Rain: Rivers Becoming Increasingly Alkaline
Posted by feww on August 28, 2013
River alkalinization threatens water supplies in eastern U-S: Study
Two-thirds of rivers in eastern United States show “significant increasing trends in alkalinity,” according to a new study published by the journal Environmental Science and Technology.
Researchers examined 97 rivers from the northeastern state of New Hampshire down to Florida over the past 25 to 60 years and found significantly higher alkaline content.
The rivers provide drinking water to big cities such as Atlanta, Baltimore, Philadelphia, and Washington, as well as other major metropolises.
“This is because acid rain, acidic mining waste, and agricultural fertilizers speed the breakdown of limestone, other carbonate rocks, and even concrete and cement,” said the researchers. “The result: alkaline particles are washed off of the landscape and into streams and rivers.”
Higher alkaline content in the water can lead to ammonia toxicity and is dangerous for crop irrigation and fish life. It also encourages algal growth and can complicate wastewater and drinking water treatment, as well as causing faster corrosion of metal pipes, the authors said.
Although the airborne pollutants that cause acid rain have somewhat declined in the United States, the legacy of acid rain remains, researchers said.
“The acid rain problem is decreasing. But meanwhile, there are these lagging effects of river alkalinization showing up across a major region of the U.S.,” said lead author, an associate professor and aquatic ecologist at the University of Maryland. “How many decades will river alkalinization persist? We really don’t know the answer.”
“This is another example of the widespread impact of human [activity] on natural systems [which] is, I think, increasingly worrisome,” said study co-author and ecologist Gene Likens of the University of Connecticut.
- Most U.S. Rivers, Streams in Poor Condition for Aquatic Life March 27, 2013